Semi-mechanical telephone system.



A. M. BULLARD.

SEMI-momma@TELEPHONBSYSTBM.

APPLICATION FILED AP.. 3, 1907. RENEWED SEPT. 3, 1913.

atee, Feb. i915.

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SEM-'vEGHANGAL TELEPHONE SYSTEM.

Hummm PELED APR. s. 19o?. RENEWBD SEPT. s, 1913.

atente Feb. 2, 3.9M

SHEETS-SHEET 3.

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.QS @s A. Evi. BULART.

smanmsmmmm TELBQHONE SYSTEM.

APPLICATION YILED APE.3,1907. RENEWED SEP'IHVS, 1913. Lggy a atented Feng, 19M.

5 SHEETS-SHEET 4.

A. Ml` BULLARD. SBM-MEGHANIGAL TELEPHONE SYSTEM.

APPLICATION FILED APR. 3, 1907. RBNEWBD s512123, 1913.

Llgl. Patente@ F810. 2, w15.

6 SHEETSfSHEET 5.

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Sismi-MECHANICAL' TELEPHONE SYSTEM.

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appncmm aies .epm s, isa?, serial no.

To all 'whom it may concern Be 1t knoivn that li. ALBERT M. BULLARD.

. citizen of the United States. residing at New Yorkin the county of New York :incl State of New York, have invented a certain new and useful Improvement in Seini-lirechanical Telephone Systems, of which the follow ing a full, clear concise, and exact clescription.

My invention relates to a telephone er@ change system comprising a number oi central otices, at each which number of lines terminate.I the oilices being grouped in districts.

My object is.I generally speaking, to provitle automatic line switching mechanism aclaptct' to be associated with a calling telephone line to select a particular district and a desired oliice in such district, 'wherein the line of a called party terminates.

viy invention contemplates the grovision oi a tlistrict selector adapted to serve a call ing telephone line hy picking ont the list ict wherein is located the which the called partys line extentie. anti to unite the ailing line with an oiiicc selector' in the selected ilist1'ict,\vhich selects the oiiice (lesirerl, :incll unites said calling' line 'with a trunk line leading to such office.

."i feature oi my invention conste the provision of a number oi keys .representing the o'liices of the exchange` each key controlling` mechanism ailapterl to operate the clistrict selector to cause the same to piel; out an ollice vselector in the flistrict wherein the .ofiice represented by such key falls, and also to actuate the said oilice selector te choose a trunk line leading to the desired. olice.

Another tentare of my invention consists inthe provision oli a controller a l:,i"f^ti to' selectively actuate said switching dev' Said controller is adapted "when set to supply proper current to the said stepping i" griets in proper succession to advance the, Contact member to the desiretiL terminals.

Another feature of my invention consists in the provision of a polarized relay. which is automatically supplied with current ot proper polarity after the long and short step magnets have (mei-ated. saiil relay thelieupon completing a. pulsating current circuit for the lifting magnet ot the contact member to advance sai member along a selected ron', said relay being maintained energized ny current at the busy trunk lines' testetl by Specification of Letters Paten `with an office selector in any district. 'i

Patented 2, Renewed September 3, 913. Serial gio.. 788,0f.

. Contact. member until an idle trunk line terminating in such row is reached, whereupon the relay is deprived of current and opens the circuit of the lifting magnet.

Another feature of my invention consists in placing a pair of stepping magnets7 in the present case lthe long and short step magnets,

in the same circuit, and supplying said cir-- cuit with current of diiierent character, one of said' magnets being responsive onlyT tc current 'of one character, and when :3p-crateri rentlering the other stepping magnet .inoperative in the forni shown, provicle tif-io magnets in multipln branches ot a circuit., said magnets being pensive to currents different strength. for example, tiventyioar and forty-eight volts respectively. The magnet `which responds only to the higher voltage current, in operating7 breaks the branch containing the other magnet (which of course would 'respond to such current) and prevents the operation thereof.

Another 'teatme ci the invention consists in the arrangen'ient whereby the operating magnets of the controlling mechanism control the application of the operating cur rents to the said Stepping magnets.

fr further feature of the invei'ition rela* to the method oit preventing access to switching device before the contact niemeerthereof, after being released at the termination of a conversation, has returned normal iuasitionlA To this enti, l provide me: us ttor maintaining the bus): condition of the test Wire, preierablyhy placing a test potential upon the multiple terminal or test wire of the switching device during the return i? the contact member to normal position.

The present invention is p: plicable to a telephone exchange ,1 the type wherein the central oiice answers the call of a subscriber way. hy uniting her conncctii the line olsuch si 4:scrit/er., ancl meenam switching mechanism completes the connection by uniting the operators connectingcircuit with the Calleri` line., the operation ("1 the s ching mechanisn'i being controlled by senoing apparatus adapted to he actuated by the operator to selectively operate .said switching mechanism. in associating is arlaptel to unite salti connecting circuit (i [to Q v i:

sending apparatus, which is adapted to be :ioeietccl with the connecting circuit, has ,acted tl'ierewit-lit zin` oiiice keyboard., oom prisi'og ireye representing the digits of the oiloes 11i the systen'x, eaeh key when deA presed by the operator actuating said d1s-- triet selector to @euse the seme to unite Suid 1 :itx-i, and. l. 1J.

means actuated when the keyboard has conipleted its Work in connection with e sending apparetus, to automatically transfer the keyboard into association with an idle sending :onueetiug circa.

- apparatus. ln` case such second or idle sending apparatus is taken for use by a connect ing circuit before the lirst sending a parntus has completed its work, the keyioard is locked iu. n. 'oeiution with seid .second send l endent of the first send g but if the second sending up fe not .aken for use, it ie mit j' re' ned to its association 've the first sem ing en'paratus when the saine is through its Werl". I preferabl provide e pair of controllers adapted to )e succes sively operated by e depressed oliiee key to selectively uotnate both the district selector and the oiee selector secured thereby.

I will describe my invention more par tioularly-by reference 4to the accompanying drawings, wherein- Figure 1 is e skeleton diagram to illustrate the method of selecting a given ollice, 2, 3 and 4 are diagrams of n portion of e. telephone exchange syst-em embodying irwentirn; and Firm 5 a diagrammen@ View of u. e switening device such ne. li employ :i ,t istrict undv an olliee selector.

The same lettere of reference indicate the seme parte wherever they'are show-vn.

Referring first to Fig.. 1, I will outline the system shown is embodying my seid invention. A district selector Z5 is provided l1fwing terminal-,e representing the districts oli the system, seid selector preferably having a number of banks of` contests, as shown in Fig. 5, seid banks each .containing one huw tired terminals arranged vin rows, each row being prwided with ten terminals repre-v senting ottico selectors in e given di. riet. Tile mutuel: member of the district seleetor is adapted, hindrance in long steps from group to group of terminals, and in short steps froinre'nv to :row of a selected bunk. Emili oliirekeyis adapted to'sel-eetirely actonte seid district `selector to piek out am. office selector in tliedistriot in which lies the ollice represented by eaid keys. A pair of controllers (l (l1 are pro'ifided for the oliie keys, eat-l1 controller having two rows of terminals. -The row o of controller G rep resiente the tens digits of the districts, While *E the 'row o1 o controller G represents the unite digits of the districts. Each olliee key, when depressed,.cl1miges the electrical con`r di ons; of the terminals in the rows f' 11 repmtiug the digitsA of `the district in which of""'; Hseutofl by suoli key lies.y For (lti is depreseed,

"i of rows o 1 'libe eont i Minimes it t from 1s Stopped, the district erm in suoli movement advancing two long steps into operative relation to the bunk of terminalsrepresenting districts Noe. 104,9. Controller G1 is now automatically brought into Servire, and in, advancing its brush 101 to terminal. 9 causes the district selector erm to advance in sabor-t steps to the row of teru'iinuls representi g selectors in district W Il", :in wliiel; oiliee No, 0 is zetel'.

loo Vj@tors (Fig. o) boing pre erlxifly pro with banks of terminale, each bank ruled preferabl' eontiunmg teu 4rows of termin-Jie, mid eorli row containing terminals olf truuk img to lgiven oliioe, each barili' rep- 105 resentido ten oilicel. The content immber of tire ,',preerubly arranged to be :idf` liront" baul' ,o bank 'iu long; steps, sliert steile from row to row of' 1 'finir'. 'lflie eo trollers (i G1' er 'o- 11 l; jmmr; .if i rmiriflls Si oli ro reprwt ting ille tens :und if" I ermimi seid. more representmgjitsdigits. ,bm

lief.'

oi" other GG muy ground the ti-rfnnfrle mi il 'and 6 of sui-tl rows. Then 'when en idle seleetor line been secured. the. brush will l' to eljiruuoe to the ground il oi" row d., therelri.7 rousing member of the Selector to edi um 4.nto operati relation to the benk of terri nuls representing iriiices Nos. `004m. 'l the bruzb lili i Mwst-xd to battery tus F controlling relay 53 ofiid sendingl apparatus, over the cpm'monfwire 50 tothe con necting circuit and thence through the armature 47 and Vbackr-eontact of relay 43, conductor 44, relay 4d (without operating the same) thence ufayv of conductor 41 through the WindingsO, 42, of relays 34., 43, res ectively in multiple (without operating re ay 43) through the armature 39 and contact, 48 of relay 34, Wire 49 to the oonductor 31 which is grounded at the armature 30 and front contact of relay 27. Relay 3i is now locked in circuit with the controlling relay at sending apparatusF.

The armature 56 of relay 34 is connected with a conductor 57 leading to the armature 58 of switching relay 4i3, the hack Contact of said armature being connected' with thecommon Wire 59 leading to sending apparatus F. The armatiire 56 in its attractive movement is adapted to separate a pair of normally closed springs 60 serially included in the ring strand 21 of the connecting circuit, said armature engaging the member of said springs connected with the portion of the ring strand leadingdirectly to the district stepper. The leads to sending apparatus F are now placed in operative connection 'with the connectingcircuit.

The relay of the sending apparatus F in. attracting its armature El applies current from the free pole of grounded battery 5E?- to the feed wire 62, a branch from said feed wire leading through a signal lamp to earth in order that the operator ma be kept informed as to the condition ofy he sending apparatus. Said feed Wire lsupplies current 'for the operation of the mechanism of the sending apparatus. In case the sending apparatus F had beenserving another cord circuit, the particular connecting circuit now in use would have been shifted to the. sending apparatus F1. It will he noted' that the feed wire of sending apparatus F has a branch. Gila which' leads through the winding G8 of the switching. relay 43' to a contact spring 6l against which the spring,v 48 of relay 34- normally rests. New, if un der those conditions the operator had plugged in to answer a call, thereby effect-- ing the ei'iergization of rela'A 27, current would have passed from the h1' the feed wire (which would have been connected with battery 52 of the busy sending apparatus) through winding 63' of relay 43 contacts (Si, 18, of relay 34, to the wire 31 which is grounded at the armature 30 of relay i7. The armatures 47, 58, of the switchingr relay would have thereupon been attracted and would have switched the wires 57, elfi, respeetii'ely, to the common wires 59.1, 50.1, respectively,,leadingto thvending apparatus: Fin-thea:meer.A when the 1w 52 with send-ing apparel (Fig, 3) throughlthe winding of the anch 62 of mature of. reilly-334 had been attracted and the winding i0 of said relay had found. a circuit way of the battery at sendin afpparat-us- `1, switching relay would have received current and maintained the switching relay energized. y

@Marmiton of office keysand datrot a- Zector.-ln' the present system, which isAdesigned foruse in a large city, there would be a number of diricts in eachA ofA which would 'be located a, mnnher of central ofices. I have accordingly employed a dis trict selector arranged to pick out the districts in which is located the ollice desired, and an oilice selector belonging to such district capable ol" picking out a trunk line leading,r to the iriarticular oliice desired. l ha ve arranged the ollice keys so that when a given key is operated it will cause thc district selectin' to locate the proper district, and also actuate an ollice selector in such selected district to select the proper oiiice. Referring now to the sending apparatus, and to the controlling' mechanism. associated therewith and known as the oliice keyboard, Fig. `2, We will describe the process oi pick ing out a trunk line leadin to a primary selector or distributor: in oce No. 08, in Which office we have assumed, the line of the called party to terminate. In this connec tion it should be ted that the ollice boaid 'is normally in lipcrative relation to the sending apparatus F in order to serve a connectingr circuit with which said sendthe holding Winding 42 o. the# nll ing apparatus may be associated; aml. when the office keyboardl haslcoinplcted its Ywork in conjunction with the sending apparatus F .it automatically transfers itseli` into op erative relation to the sending apparatus F", and if the sending apparatusA 1*" is taken for use before the first mentioned sending apparatus has completed its work, said oiice keyboard will be locked in its operative relation to the apparatus lil. However, assumingl that the second .sending apparatus is not taken :for use, the ofli'ce keyboard will, after the sending apparatus F has completed its work, he re-associated with sending apparatus F.

The oliice keys are provided, with a pair of controllers G G', which govern the operation `of the district selector and the oice selector which it selects. The office keys are cach adapted when depressed to efect the successive operation of the controllers G' and Gf to cause the same to efectthe op eration of-the district selector' and pick; out a district'- determined by the particular office key depressed; and thereupon the controllers are again successively operated to actuate the selected oliice selector in said dis trifft. .leierring iii-et to controller there is provided e rowof contacts c` numbered trout 0. te 9., tival eremita representing 'lilli y in tens digits' of the numbers of the dhtricts. From each one of said terminals a conductor G5 leads to the springs 66 of the particular oiiice keys representing oliiees lying in the district Whose tens digit corresponds to the number ef said terminal. ln the present case l here shown springs di ollice keys Nos. 0 and S as connected with the O ter iinal of the row (f ot' contacts. The controlle fil is provided with a rotary arm TG carrying brush "il -adapted 'to sweep o the rou' e of contacts, said arin being provided with a ratchet adapted he op erated by stepping and retaining magnets i2, 73, respectively. The brush "il 1s con nected with a conductor .74- Which leads through springs associated with cutoil relay i6, winding of said relay to thel leed wire l? oi the oilice keyboard, 1which is normally connected through the arma-- ture T8 and baci: contact of a switching relay 79 with the feed -Wire 62 of the sending apparatus F.

Each oiiice key, when operated, is ranged to bringinto electrical engagement springs 67, G8, 69, which control the starting of the office controller or keyboard after the sending apparatus Vwith. which it is assi'iciated has connected with particular connecting circuit The spring 68 is connected with the feed Wire l? and so with the battery of the sending apparatus, and

in engaging spring 69 supplies current to a signal lamp 80, which indicates to the oprator the condition of the ol'lice keyboard. T he spring 6T, supplied with current from the feed wire by spring 68, is connected with a conductor 81, which supplies current to the operating magnets of the controller G, said conductor leading through the retaining and stepping magnets 73, 72, respec tively, oit arm 70, through Contact springs S2 associated with the eut-olf relay TG to a grounded vibrating arm or pulsator 83. The stepping magnet 72 responds to lthis current and advances the contact arin 70,

the retaining magnet being sluggish, so that its armature when once attracted is unresponsive to the pulsations. `When the con` troller arm has taken one step and the brush Tl has engaged the first terminal of the row c, the cut-oil relaiv 76 is operated to open the circuit of the magnets 72, 73, oi the controller, current to operate rela)7 76 passing from the feed Wire 77, conductor 74.

winding of relay 7 6, contact springs 75 as-v engaging rie ineinber of said spring connected "lire with the pulsator 83. lhe

c other armature is grounded, and in its attractive movement separates springs, 75, engaging the ineinloer tliereoffI connected directly with the Twinding of relay i6, thereby locking relay 'lo 'to earth from the feed wire.

The stepping magnet l2, in operating, is adapted to nialic and hrealr a pair of contacts d?, which control 'the application oif oui-rent from the A,tree pole ein grounded positive battery S8 to a conductor Si) leading to eonunon wire 90, which is normally con nected at the arniatur 91 and back contact oi a switching relay 79 `Titli the common wire 59 of the sending apparatus l?, in the present ease, since this contact arm advanced out one step, l; .t one impulse or' current would supivilied hy contacts 8l :from hat tery to the common wires Q0, 5S), the conn nien uire 59 being, as before described, con nec-ted by the armature 5G and front contact ci relay 3l, B, with the portion of the e strand of 'the connecting circuit leadto the district selector'. 'lurning now te he district selector, a niunlier of groups of erininals are provided, each group reprethe terminals silice selectors Caper toning oilices in a given number @has the selector iay have .its

divided into ten s ,su` rows,

`ticular silice, and the total n the group representing the oliicc selectors in ten districts. A brush carrying anni 92, mounted ,to rotate and to more longitudinally, is provided for the district selector, Fig. having a long step magnet adapted to rotate the arm in long steps, ifor example, over ten rows of terniinals at a step, in correspondence with the tens digits ot the district numbers; the step ping magnet (Jl is a ranged to advance the arin from rou' to rou' i a. selected group, wli'ile'tlie stepping in adapted arni up\.ai'di e brushes carried ther la); into connection ywith a set or terminals in the selected row connected with idle oiice selector. Frein the strand of 4the connectingcircuit, the conductor 95 leadsI throueh a pair of contacts 96 closed by the arin u'uile iu its normal and rotary positions, through the winding of the short step magnet 94, armature- 96 and back Contact of polarized relay 9i', through the contacts. 9S of the retaining magnet 3G, to earth. A conductor 98 extends in shunt of the stepping magnet 9i, said conductor including' the long step magnet 93 and the arniature and hack Contact of the stepping magnet Vlfhe stepping magnets 93, 9%, are so arranged that the magnet 93 requires for its operation a smaller amount of current than Ad into groups ol' one liuui Lief . i conductor l' tlint flint inognetQR muy open magnet Q4, so

' magnet 94;,

cmd, in the onine circuit with the n no n t, ting y', 3i: i 'npr ed L)on circ in in ting 'its firmati e opens;

nding tl;

tl'o ving 533 renewed nnlliizlen't om for f `tion 'sind roti-.ized thc clin l f i. the seleilel. tllroufgii one long Step,

to tile` iirst'bank of, tonrows of terminals of the district select-or, said bank representing the first ten districts- Returning now to the ollice keyboard; 'tl-1c second controller Gl" at this point' brought into play to complete the selection of a district by causing the dis-- trict selector arm to advance to the row' of terminals in the first bank determined by the nn' digit of the district in which the pon ticui'nr oilicc l'. located,

98 le keys repre office will lie in the c 'winds 1 gits corr nomi to the nni'nocis of tlv-,c imm-initials in thchrow ci; that to say, taking the case of oiiice Nol Mythe spring' 99 ofwsncli oilicc key is con fated with, the terminal 5'9" of the row' c", onli' il'idicatcc that the unitsdigil; ofthe, di.. 'et in'which is lo'cntod"l:il o 'No O" il, llt should lie n und, liowi; er,

nifinngeiinent is purely arbitrary, ming; of olicc ,key No, 8 could cx woll lieve been connected with an'- d'epentli'ng of .einen is, alctly 'nie other terminal of tlm, row ci.

con

T le spring; {l} of ckline key N cngogement 'Willi eration of key No. 8, and by means of said spring a plies ground to terminal 9 of4 row of* ol conti: llci G1. The cmitroller G- is provided with a rotary crm 100 carrying o brush 101 adaptedto sweep over said row of terminals, said crm. being .rosfidcd with n stepping mu ct 102 an s retaining magnet 103; Now, when the cnt-ofi' relay TG woo' o cinted to stop the o )om tion of con l :r 1, as before dccribc' it started' the iion of the controllerY GK The armaoi .relay Til coi'nicoted with n con tino, 1W, which lends through tinicom 1r-M splhl if th eutolf roll-ly 1M oil with the grounded terminal 9" controller G1, through. the stepping-'magnet lllof controller G, contacts 105 close by tlie'controller arm while in normal position, tlinongli the retaining magnet AL03 to the treo polo of n grounded battery 'llli Since the #iront Contact of the armature 86 of' cutol relay 7G isconnected with conductor 81 and grounded pulsntor 83, a circuit 102, 81, will be completed for the magnets 103,102* of the controller G1, and pulsations of current from'buttery 1106` will pass through said cir-` cuit, 4,causing the stepping ma net 102 to advance the arm 100. It chou d be stated at this point that tho'contncto 105 arc for the purpose of preventingr access in the con troller arm 100 unless th same is in normal position. The contc are opened as soon as the arm has taken one step,vbut n branch 1U? about, said contacto is closeli" by the iw mature of the rctainn magnet 103', which is sluggish and maint ins its armature attracted regardless ofthe pulsatingljchamcter of the current in its circuit, sai armature when attracted clo'sin a pair of contacta 108 which control the sai branchl lili'.

` The armutureof th'ste pingimagnot 162 in its vibration makes an, breaks `a pair of contacts 108", which intermittently applica current from a grounded battery 109 to a conductor 11,0 whichl leads to the eck; con tact of the armature 111l of n relay 1122, mill armature being connected by c comlcctor 113 with the common wire U0, und so with the ring strand 21 ofthe connecting circuit, lmpulsesfron battery 109 Lo tile conducto at the district ,il thence through the step ing magno?, M of the arm 92 yto earth. hin current is of proper-strength tn operate magnet ill, proferably -lvloltsi Said, magnet @1in oper-ub ing ad'vmices the arm in. snort stops from row to row of the first ronp of tcrminnls, and' in addition, opens t ie branch *.38* containing tlio long step magna; in order to prevent, its4 operation. r

,loads through o winding 115 of u sluggish l relay 112, through contact springs llfof n cut-oli relay 104, winding of said relay, to the feed' Wire 77. Now when the arm 100 hns been given ten steps,t and the arm of the district selector has been given a like number of'ste s, so that itebrushes lic below the now' terminals representi o'lce selectors adaptedto reach offices in st'rict No. 9', the brush 101 lwill be .in enga ement oL c row el, and current will flow from the feed Wire 77 throufthe winding of e cutoff rela 104:, win ing' 115 of sluggish relay 11g,

springs 99, 84:', of office kcyNo. 8,

Ski

ico

. tractirc nimcnicnt cnniplct'x The cut-cil" re ay 105x is provided with paar ci armatures i1? liti; thc arnizrtiuIr MS, when attracted, separates thc spi' l n 103L to @pen the circuit ot the operating niagucts of thc controller Gli While the armature 11T, which is grounded, in its ati 5min` tractirc'nim'cnicnt scparatcb gs 16? cir gaging thc mcuibcr thereof conncctcd dircctly with the winding of thc cut-013i rciay pchirity a grounded nega i, #Liu this battery ism a proper poiari atc thc pclarizccl relay' il?. at the g. ct lector. which controls thc hunt 'thc arm L 92 fo an idlc oiiicc Selector capiihlc rif reach ingr thc olhccs in district No. i). C i" from. said ncgaire battery pascs common wirrw 90.1, 59, and ling Strf thc district sclci.. ci', whcrc Said cri crsc-.s conductor 93 to cnc of thc in contacts 9G7 which is normally' Vith a sprinfr i2?, and thcncc over durtor if l tl,M ugh thc armature l front contact ir) thc rctaining mag" 7 Winding' ot relay Si' and contacts if i, cicscd by thc arm SW u'hilc away from ucrmai @csition, to earth. Thr b'tcpping magnets Q3, 9"', ilo not respond l'c this current, on account @if the rapid attractive increment ci the armi turc 55H3 Ot' rclay 9?, which contrcis; thc ci?a cuit of said magnets. clay 9?, when thus upcratcrl, attractf; its arinaturcs ir, lt 96 and 1Q?. r he armatures 1'25q Sinr ply maintain thc liuc hrushcs of thc (listin selector clcml riuriug thc aunt "n uliicc Sflcctur; 11h01 armature 9 in l.

:i circni gating cui-rhin; 129. by way m conducto and 955 .vhcrcirpou thc arm .ii'l'tbringr its brush` into f ngagcuicnt with thc first trunk liuc tcruiinnla in thc. sclcctcli ruw. When thc arm habt iakcn its' first. Stop upuarfi, it :1 aI:itcI-: spring lil 'from thc cm tzu-ts; 9G and uuwcf: .Haill spring into cnyagi mout with a contact im). which is conucctcd with a coiuhu'tcr L, lczuling t0 thc front contact arl' thc armature .12T of relay 9T, which armature in turn is conncctcri by a conductor with thclocai brush L35 car-- ried hy the sclcctcr arn. The relay 97 is now conucctcii (iircctiy tu carih ''rinn 'thclocal bruSh by Way 0i' condur- 131, '100 and in carc thc aid .first @151011, Bain hattcrj he. present at thc 13?,- thcrcot, of a proper pontain rciay 9T energized, wherc- (arr-uit ci' the stepping magnet 95u i'mintaincci intact, and thc afin 92 lii'tcf another step to bring its brushes into cngagciucut with the terminals 0i' a second trunk line leading to a Selcctor scri'ino oi- 'rccs in district J This operation will he routinucd untii thc Contact brushes of thc arm ik reach the terminals of an iclie trunk liuc, ai which tinic iattcry will not he prescnt upon the iocai tcrininal lf3-i of such uil' line, ai; i thc will be deprive@ Ulf current and Wiii release its arniatur arniaturc 9(3 Opening the circuit of thc lift# ing magnet 53, and armature 12T applying its hack contact current from a battery tu conductcr 132 anti the local brush in order t@ lock cut other district sctc maize cmincctimi 'with t? in question.

Clerc' 'zon of ojfzfcc ic-Leim' mida #Le cmi- .f'ml f Le depressed (ij/30e fc3/, The trunk linc selected by the district selector 'leads in thrcc bs 135, 137 and to :in oiicc selifiw'. l?) adapted to malle connection t iin@ leading .tc prim" desired c'lice in rhs fict provi lcd with rascnting trunk iincs in district No. O9, cach a mit' of tcriniiiais in Said niiicc c said oiiicc sei-actor is con ar to the district selector (Figi 0'? terminals being arranged in for cfzanipic ten rows to :i group, r adapted anu thc arm ci inc Scicc't ne moved 1n l0l Step from' group to gr up,

s in hort steps t@ Scl ct a particular 110W of 'the said group and. iongitudinaiiy along the selected rmi' to an itil@ tcrniinai therein.-

When current was app icd :it thc district sclcctcr :from battery 1.5 to thc ical brush W" @er ci' the Ytrunk line sep; niafrnet ci thc ciice.

il u 1.,'.

, H10 was operated hy said current passing over conductor 13S ami throu h sani inaffnct tc earth by way of' Springs f Selector in normal conmagnet, Whe cncrgizcd, attracting armature 347i, :rmi iccking itselfY to earth from conductor H38, inricpcnr'icnt 0i thc said springs. The clhcc selector arm is arranged to harca rotary movement by long and short Steps, and an up *fard inox/"ement, and saic'` arm provicicd with a long step iuafnc; HQ and a short Step niagnct M3 inriuscii ri hi? i-iuicii in parailcl hranchcs 144., 144, oi' a conductor 14:3, which loads from the, line conductor 132713 through contacts 146 moscd by thc arm until. t arts its npthe i t innvcincnt, to earth through 'rature i-i hack Contact of l positive current employed A.tu npenate the step magnets 1&2, l113. ALS in Acane of ther trct selector, the long emp magnet responeive to ,cumfent of low voltage, for

lexample volts, while the short etcpmng uct .is unresponsive to .such .current vbut requires for its .operation .current .of ahigher voltage, for example, .118 Molta, :and Ain .ntf tractuig ite armature opens the'hranch :1M containing the long ystep magnet ato vprevenir its ope-ration. The upward movement vofthe selector ,arm is controlled ably a lifting magnet 118. l

After an yolice selector .of dixtricttNo. 09

has been selected, .the .controllers G, G2511@ cessi vely cooperate `with lthec lcpreeaecl niA key No: 8 ,to aotuate the selector .and select u trunk line leading ,to :the Voice desircd. The controller G'Iis provided with u row d ci ten-terminale .correspondinglto ,the tens i digits of the oliice numbers, and scid terminals are connected with conductors 149, which lead 7to the yspringe 150 of .the keys representing .o iiices whose tens digits correspond withthenumher of .such terminals in row d. Each ,of said springs 15G-is adapted when operated to engage yolgrounded v:spring 1:31; thus in the present cu'se, since milice/:ice No. 8 is depressed, itS tens digit V,being 0", u ground is .applied hy the springs 1,50, 151, to the first or t'lft 'minul .of the row d. The arm of t if ntrollorA G carries u cond brush adopted to sweep over the row of terminals d, said brush being conv nected with a conductor 153 which leads through contacts 1511 .closed hy the retaining ,magnet 73 of controller 4Gr when energized, through contacts 1.55 closed hy the cutoff relay 101 of controller G1, (which rel-ay now locked to the feed wire) through Contact springs 156 of relay 157, winding of Suid relay to the feed wire 77.

The operation of controller G to advance the oliice selector arm is controlled :by relays 1li-l, The relay 112 when dcnergize :lifter controller G operated, placed relay 1.58 in condition to have :t circuit therefor completed at the Selected olice selector, said relay 158,'when operated, starting controller (l. The relay 112 was operated momentarily to start the automatic selection Aby the district selector oa trunk line leadin to an idle otlcc selector, and when said re ay r0.- tracted its armature 159, it ap lied current from a positive battery 160 (ihr example) to a conductor 161, which leads through said armature 159 and hack contact of relay .112, through the armature 162 and -front contact of: relay 104, through the normally' closed contacts 163 .of cutfoil' .relay 157 associated with the controller G, throuh normally closed contacts 164 openedby t e retaining magnet 73 of controller G when energized, thro h the relay `158 to thezcom mon wire ,90, i, `ow `v wlnaxx,tlxe districtigehe wr has pickedputa trunk line ledixrglto an oice selector, and relay 917 has become de energized, .und 'thas ,retracted its armatures 125,126, current from said battery 160 at the oflice keyboard finds a path over conductor 161 through the .winding of relay158 (relay 112 having now retracted its armature`19') ,to common wires v90, 59, ring strand 21, ,through the line contacts of the district selector, to the line or trunk conductor 1137, and thence to ,the ollice selector and y(through vcomiuctor 145 and stepping magnete of the Aoflice selector, to earth. The long Jstep magnet of the selector i'operated by .this current and advances the seleco tur arm 2eet/ep, `which is merely incidental to the operation.

The relay 1,58 of the controller G in utuncting its armature 165 completes a circuit for .the .operating Vmagnete .of the controller Gsaid .circuit extending from the feed Wire 717 through springs 67, 68, closed by the office key when operated, rconductor 81', retaining mago of .the arm 70, through contacts 166, which are ,closed While .the erm 70 is in nunmal position, conductor 167, armature 166 and front contact of the relay 158, contact springs 168 ,of the cut-oil relay 157 of controller G, .to the armature 118 of the cutoff relay 1010i .controller Grl (which isnow ,euergizedin a locking circuit from the feed wire), thence by way of the front contact of said armature -118 to yconductor 102 armature 86 and .front contact of the cut-cti relay 76 ot' controller GV (which is also energized in n locking circuit from the feed wire.) to lconductor 8l and the vibrating grounded arm. `The stepping magnet 72 is now operated to advance the arm 70 und th retaining magnet 73 attracts its amature, which remains attracted regardless of the pulsatorl character of the current in it circuit, sai armature opening at contacts 164 the circuit of relay 158, and closin at contacts 169 a branch conductor 170 a out the armature 165 and front contact of relay 158 andy lthe contact 166 of the controller arm, both of which sets of contacts are now open. The contacts 166, which are initially in the circuit of the stepping ma et 72 are for the purpose of preventing t e operation of the controller arm 1t is in normal position,

The vstepping m et 72 in vibrating its armature operates t e contacts 87 to apply current -from the 24 volt battery 88 of positive polarity to conductor 89 and common wires l90, 59, cord strand 21, through vthe district selector line contacts, trunk condimtr 137, to the otllce selector, and thence by way of conductor 145, through the magnets 142, 143, in parallel, to earth. h1; current ,o .etes sim ly the long step magre the et v73 and stepping magnet 72 l' lll tor. arm in long steps from bank to bank of the terminals.

Then the controller arm 70 has taken one step, and the office selector arm has been rotated through one long step into operative relation to the first bank of terminals, the brush 152 of controller G engages the first terminal 7 in the row d, and a circuit is completed from the feed wire 77 through the cut-ofi' relay 157, conductor 153, contacts 155 closed b y the cut-od relay 104 of controller G1, contacts 154 closed by the retaining -magnet 73 of the controller G,

brush 152, L0 terminal, conductor 149 tol ground through the contacts 150, 151, of

oiiice key No. 8. The relay 157 is now energized, and attracts its armatures- 171, 172; armature 171 sepa-rating springs 156 -and engaging the member thereof connected di rectly with relay 157, said armature being grounded and completing a locking. circuit for the relay from the feed wire. The armature 172 in its attractive movement separates springs 168, opening the circuit through the operating magnets ofcontroller G, said armature also serving to bring into play the controller G1, which causes the oiiice 'selector to advance to the row of terminals of the selected bank representing trunk selectors adapted to pick out an idle primary selector at the desired otiice.

The controller G is provided with a row d ol" ten termina-ls representing the units digits of the oliicelnumbers, and from said terminals conductors 173 leadto contact springs 174 of the office keys representing offices whose units digits correspond to the numbers of such terminals of said row d1. Thus in' the present lcase contact spring 17 4 of key No. 8 is connected with the 8 terminal in said row (Z1, said spring, owing .to the operation of key 8 engaging spring 151 which is grounded.V The controller 'arm 100 carries a brush 175 which is adapted to su'ccp over said row nl of terminals until it engages the terminal which is at which point the circuit of the operating magnets of the controller is broken. The said brush 175 is connected with a conductor 176 which leads through normally open f -ontaets 177 closed by the armature of the retaining magnet 103 of controller G1 when attracted, through contacts 178 closed by cut-ofi' relay 157 ot controller (i, Winding 179 of sluggish relay 112, contact springs 180 and a cut-olf relay 181.- to the feed wire 77.

As before stated, the armature 172 of the cut-ofil relay 157 of controller (i controls the operation of the controller G1 in its relation to the oliice selector. When said armature is attracted a circuit is completed from the free pole of battery 106 by way of conductor 102 through the vretaining magnet 103 `at conti-011er G1, contacts 105 closed when the rounded,

arm 100 is in normal condition, stepping magnet 102, conductor 182, normally closed contacts 183 of cut-oli' relay 181 of controller G1, through armature 172 and front contact of the operated cut-0E relay 157 of controller G, conductor 167, armature 118 and front contact of operated relay 104, back to conductor 102 and thence by way of armature 86 and front Contact of cut-ott' relay 76, conductor 81,- to the ground pulsator 83. The retaining magnet 103 in said circuit, when energized, attracts its armature, Which closes contacts 177, completing the connection of brush 175 by Way of conductor 176, with the feed Wire, said conductor including the cut-off relay 181 and winding 179 of sluggish relay 112; the retaining magnet also closes contacts 108, completing the branch 107 about contacts 105, so as to maintain the stepping magnet circuit independent of contacts 105. f

The armature of the stepping magnet 102, in its vibration, operates the contacts 108, applying impulses from the positive 48 volt battery 109 by Way of conductors 110, 113, tn 90, 59, cord strand 21, trunk conductor 137 to the oiiice selector, and thence to earth through conductors 145 and 144, including which rotates the selector a"m in short steps Jfrom row to row of terminals, and maintains open the branch including the long step magnet. When both thc controller arm 100 and the otiice selector arm have taken nine steps and the oice selector arm is in operative relation to the row of terminals representing primary selectors at office No. 8 1n district No. 9, a circuit is completed for the cut-olf relay 181 of controller G1 and sluggish relay 112, said circuit extending from the feed wire 77 over conductor '176, brush 175 and terminal 8 in row d1, conductor 173 to ground at office key No. 8. The cut-oi relay 181, when thus energized, attracts its grounded armature 185 which separates springs 180, breaking the connection of battery with sluggish relay 112, and brush 175,-and engaging the member of said springs connected directly with the relay 181, to include said relay in a locking circuit from the feed wire. .The armature 183,

.when attracted, opens the circuit including .from the'n'g'etiy battery 120, 'by of lso I conductors 119,113, to common wires .90, 59, cordstrand 21,- trunk conductor 137, tlirou h one member of contacts 146 controlle by the selector arm, to a spring 1841 connected with a conductor 1851 leading to earth throue'h the winding of a polarized relay 148, which responds only to negative current. Relay 148 is now energize and attracts' its armatures 186, 187, 147 and 188. The armatures 186, 187, interrupt the continuity of the trunk conductors 136, 137, leading to the line brushes u on the selector arm, to maintain the said ine brushes dead during the upward hunt of the arm for an idle trunk line. The armature 147, when attractedz completes a circuit 189, includin the lifting miignet 148l and a source of pu sating current 190, whereupon the arm is lifted to bring the brushes thereof into enga ement with the terminals of the first trun: line in row 8 in the first bank of terminals. At this point the contacts 146 are separated and spring 185 engages s ring 191 which is connected with j the con iictor 192 leading to the front contact of the armature 188, and through said armature to the local brush 198 of the selector arm. The relay 148 is now connected directly to earth from the local brush 193 of the selector arm through its own armature 188 and front contact, springs 191, 1841. Assuming that the first trunk line 1s engaged, negative battery will be present at the local terminal thereof, and relay 148 will be maintained energized, and in turn will continue the continuity of the circuit 189 including the lifting magnet, which will advance the selector arm to the next set of terminals, and so on until an idle trunk line is reached, in which case, no potential will be present upon the local terminal of such trunk line, and relay 148 will become deenergized, retracting its armatures, armature 188, when retracted engaging a back contact connected with conductor 194 leading through the armature 195 and front contact of retainin magnet 189 to the free pole of a grounded attery 196, such current applying a test otential to the multiple local terminals of t e selected trunk line to lock out other ofiice selectors.

Dsconnectz'on of oice key/board from sending apparatus F .--When the oHice keyboard completed its work in connection with sending apparatus F, it was automatically transferred into operative relation to sending apparatus F', and the de ressed ofiice key and mechanism of the ceyboard restored to normal condition. It will be remembered that after the short step magnet of the oliice selector had operated, the relay 112 was momentarily energized to start the automatic selection by the selector arm. Said .relay in retracting its armature 159 supplies current` from battery 160 to oonductor 161, armature 159 and back Contact of relay 112, armature 16'2 and front contact of cut-oli` relay 104, to conductor 254, which leads through the armature and front contact of cut-ott relay 181 and winding of test relay 158 to the common wire 9b. Now when an idle primary selector has been selected at oilice ilo. 8 current from said battery 160 flows through the relay 158 over the common wires 90, 59, conductors 21, 137, 198, through the bridge 230 at the selccted selector (Fig. 4) and back by way of line conductors 197.l 186, 20, to earth at the iirmature 54 and front Contact ot relay 34 (Fig. 3). Test relay 158 when energized in the said circuit serres to complete a circuit for the switching relay 79 which transfers the feed wire 77 and common wire 90 to the feed wire 62 and coniinon wire o9' oT the sending apparatus li". The said circuit for relay 79 extends from the feed wire' 62 I of sending apparatus l", conductor 257, through the winding 256 ot switching relay 79, spring 258 and its back contact oli a polarized relay Q59, responsive, for c`\an'iple. to positive current only` through contacts 260 of the cut-oti relay 181 of controller G'. throu'gh contacts Q61 oi said test relay 158 to earth through contacts Q62 of the relay 263 at the sending apparatus F', which relay may control the starting of the primary controller of such sending apparatus.

'lhe switching relay 79 is adapted to transfer the ofiice keyboard to thc sending apparatus F in such manner that should sending apparatus li" be taken for use before apparatus F completes its work, the keyboard will be locked in association with sending apparatus li". lf, however, the sending apparatus F is not taken for use before its mate is through serving a given cord circuit` the keyboard will he rcstored to its normal association with sending apparatus F.

The' switching relay 79 when energized by current in its winding Q56, attracts its armatures 264, 78, 91 and Q65. The armatures 78 and 91 connect the wires 77. 90 of the keyboard with the wires 62 59 of sending apparatus F'; the armature Z6-4 engages a spring connected directly with the feed wire 62 and completes by way of conductors 266. 257, a locking circuit for the said switching relay controlled bv relay Q63 of thc sending apparatus F. The armature Q65 ot said switching relay is also connected with conductors 266, 257, leading through the contacts 262 to earth, and said armature in its attractive movement engages a spring connected with a conductor leading through a winding 267 of the switching relai' to tho wire 62 of sending apparatus l". so that when current is applied to the said toed wire 62 by the armature 61 of the controlling relay 58' of sending apparatus 1r'7 mid switching relay will maintain the .association of the oflice keyboard with the sending apparatus F independent ot' the condition of the sending apparatus F Resto-ration of' depressed oyjice keys. The oh'ice key No. when depressed, was locked in such position preferably by means of a locking bar having openings therein througlrwhich all the key plungers project, each key-carrying a. conical latch member adapted when the key is depressed to engage the under side of thc said locking bar. Said bar is adapted to be moved by a release magnet 206 to release the 'depressed key. Said magnet is included in a conductor 267' which leads to a pair of contacts 268, one member. whereof-,is adapted to be engaged by the armature 269 of a sluggish relayT 270, said armature being connected with thc free pole of a grounded battery 271.- Said armature 269 in itsret-ractive movement is adapted to effect momentary electrical ehgagement between itself and both members of the contacts 268 to apply current to con-I ductor 267' and operate said release magnet.

The said relay 270 is included in a. con ductor 272 which leads to normal resting contact of a spring 272' adapted to be operated by the armature of the polarized relay 259, said spring being connected with the feed Wire 77o1c the otiice keyboard. When current is applied to the feed wire 'ifsending apparatus F, it passes by way of the feed Wire 77, of the ofice keyboard,

through the spring 272' and back contact of relay 259 to conductor 272 and relay 270 to earth. Relay 270 attracts its armature 269, separating springs 268. An impulse of current is thereby delivered frombattery 271 to conductor 267 and release magnet 266 to earth, so that in case an oflice key` has been accidentally depressed, it will be restored. Now when the oice keyboard hasv performed, its work in connection with sending apparatus F, the switching relay 79 yis operated as before described, and removes at its armature 78 and back contact. current from the office feed wire 77, Whereupon the relay 270 is deprived of current,

and its armature 269 in retracting applies current to operate the release magnet 266' and restore the depressed key.

Restoration of office ccy/ when keyboard serving sending apparatus F'.-Assurne for a momenty that the otlice keyboard is serving the sending apparatus F' and that current from the battery 52 at said sending apparatus has been applied to the 'feed Wire, 62. l posite polarity from corresponding battery This current being ofA opat sending apparatus F will ,operate the polarized rela'y 259, said current* passing.

fromtheleed wire 62 through the armature 78 `and front contact of" the switching relay 79, to the feed wire 77" of the oflec member whereof is connected with conductor 267'. said armature vbeing'connected with the free pole of a grounded battery 273' and serving to apply impulses to the conductor 267' to operate the release. magnet '266'.

liasfmwzffl-n of' .leg/board to ,sending lp/)(r- /wf'f/s [Qn/'fer sfr/'ring sending apparatus 1"".-\Vhen the oiiice keyboard is through serving the sending apparatus F', the rela-,v 263 is operated todeiinergize relays 79 and 259, which thereupon restore the association of the otlice keyboard with the sending apparatus-F. Said relay 15S when operated. at thy completion of the service ofthe keyboarrh completos a circuit from the feed vn-'e 462.' of sending apparatus F', through the winding of relay 263, contacts 274 of `said relay,.to a conductor 275,`which leads to4 the frrnit' contact of spring 258 of polarieed rela); 259, and thence by way of conductor 257', contacts 260 of cut-ott' relay 18].' contacts 261v closed by the relay 15S, contact-262. of said relay 263 to earth. Relay 263 is ,energized in the said circuit and attracts its'armature 2,76'which is grounded. said armature opening springs 274;,- and engaging :rmem'ler thereof connected directly with the' lpinning ol relay* 263, thereby locking said relay to earth from the viteed wire 62. 'The armature 262 df said relay 263 opens the locking 'circuit of the switching relay 79 from said feed 'wire 62', \\'hereupon said switching relay restores-'at its armatures 78, 91 the connectionof wires 77, 90. of the oilice keyboard with the wires 62, of sending apparatus F. The armature 7b' oi said switching relay in its retractive movement disconnects the feed wire 62 from the circuit of the polarized relay 259, which thereupon releases its armature, moving spring 272' to break the circuit of relay 270'. which rctracts its armature 269 causing ,an impulse of current to pass through the releasel magnet 266 of the oilice keys.

Summary of operatvun..-Having now described in detail the circuits shown as embodying my said invention, I will endeavor to give an outline of the complete operation of the system as brietiy as possible. I will assume that the subscriber No. 999 shown in Fig. 3 desires connection with subscriber No. 2749 whose line terminates 'in-oice' 07 in relay.-

district No. 09; The operator p on observ- 999, inserts her answering plug into the jack of such line, and depresses the listening key of lier connecting circuit to inquire the number wanted. Whenl tie answering plug is inserted in the jack of the calling line, the sending a )paratus F is automatically associated witi the connecting circuit b v means of the relays 27 andl -l. The relay 27 is operated in the circuit completed b v the operatoi"s connection switch, and in turn com )letes an initial circuit for the relay 34, wiiich thereupon at its armature 39 completes a locking circuit for itself, said relay 3l at its armature 56 connecting the common wire leading to the sending apparatus withy the link conductor 2l. The controlling relay 53 of the sending apparatus is included in the locking circuit before referred to. and when operated ap )lies cui'- reiit from the battery 52 to the fee wire (i2, whereupon the sending a puratus is placed in operative condition. he o `ieratoi, upon ascertaining the number of tiie subscriber desired. which we have assumed to be 1465, in oliice OS of district 09. depresses oiice key No. 8. 'l` he ollice key depressed starts the operation of the oflice keyboard to actuate the district selector associated with the connecting circuit and pick out an ollicc selector in district O9. 'l`he retaining magnet of the district selector is included in a circuit controlled by a relay 27 of the connecting circuit. Oflice No. 08 being located in district No. 09, the ollice key No. 8 when depressed. applies a ground to the 0 terminal of the row c of controller G, and to the terminal 9 of the row c1 of terminals of controller G, these terminals representing respectively the tens and units digits of the district in which the desired line is located. The oliice key when depressed, operated contacts 67, (S8, G9, to start the o )eration of controller G, said contacts completing a circuit for the operating magnets 72, 73, of said controller, which advance the controller arm, said stepping magnet 72 applying current from battery 88 out to the district selector to operate the long step magnet 93 thereof, thereby advancing the selector arm in long steps rom bank to bank of terminals. cach bank representing ten districts. When the controller arm luis taken one step and the brush 7l reaches the grounded terminal in row c, the district selector arm lies in operative relation to the first bank of terminals representing the first ten districts. At this point the cut-ofi' relay 76 of controller (i is operated and stops the movement of the arm of controller G, permitting its return to normal osition. Said relay 76, in operating, switc ies into service tliecontroller G, completing an operating circuit for its operatinglmagnet 102 and retaining magnet 103,v w ereupon the we of ,Seid .centrale Si? .e einen@ .reid

.1d-Fidelio? its brush 101 sweeps over the row of terminals c. rl`lie stepping magnet of the coutroller serves to apply impulses of current from the battery 109 to the circuit of thi` Short step magnet 94 of the district selector arni, which magnet thereupon advances the selector arm in short steps from row to row of the selected bank. When the brush 101 of the controller (l reaches the terminal grounded by the depressed ollice key, the selector arm will have advanced to the last row 'of terminals in the iii-st bank representing district 09. Thereupon the cut-ofi relay 104 of controller (il will operate to stop thc movement of the controller urni and interrupt the impulses supplied to the district selector.

relay 112 was operated in conjunction with the Cut-oil' relay referred to und applied a. momentary impulse from buttery 120 to the conductor leading to the district selector, said current passing through the polarized relay 97 at the district selector and icing of proper polarity to operate the same. Said relay thereupon starts the operation ofthe lifting magnet 95", which lifts the dis trict selector along the selected row to pick out an idle ti'iink line leading to an oilice selector in district 09; the polarized relay receiving current from the loc-.il conductor of the busy selectors to maintain the circuit of the lifting magnet. When, however, an idle selectorllias been found, thc relay J7 is denergized, breaking the circuit of the lifting magnet and applying a test potential to the row of terminals of the trunk line leading to the oflice selector. The depressed olice key No. 8 applied a ground to the O terminal of the row d of contacts of con troller G, and the 8 terminal of the row d1 of contacts of controller G1, said two terminals representing the tous and units di its of the desired oilice. The said relay 11 when de'energized, connected a test relay 158 160, to common wire 00, and said relay 158 found a complete circuit when the district selector had united with the terniinulsleadin to an idle oflice selector, current from said battery passing to earth through the stepping magnets of the ollice selector and serving merely to give the selector arm an incidental long step. The relay 15S, when thus operated, brings into play the controller (i, which causes the selector arm to advance into operative relation to the bank of terminals in which is located the terminals representing the desired ollicc, cach branch comprising,r ten rows of terminals representing ten ollices. Said relay 158 serves to complete a circuit lor the stei'ipiug magnet 72 and retaining magnet 7B of controller G, the retaining magnet in operating completing said circuit independent of the LOO in a conductor leading from battery testv yrelay and rendering operative the nf'mslw. 3; Ci m minimis nder. cfcitfo L he EL magne.. The stepping magnet 72 im eration appes impuses of Cuman from the battery 88 over tha-Hunk conductors 30 the @Hice selcox, "Wham said curren passs hrough the sappug magnet A@ to QmtL.,

avancng aha arm in. olg steps. When rm has-taken one imag; Siep into opel-nm engaged in@ wrmaa grmmml. by Hm presse @Hice hay? and im cut-off l5? will @param amd ope?L the Ccu of the bp @rating magnets @if fue aontlole; thebj; cutting G' the suppv of current to me Qfce 15916060?, The cut-off @my 157 in opeangj stazts h@ cent1-@Her G1, which causes iihe 2@ oce Seestox' arm to advance in short st'eps from mw "an row of erminas in the Seecsed Dank imo' opemyve 'e'laton-t the row of ermnags reprfsantng Gce No. OQ. Said relay operating compees a crsui im? the stepping magnet 102a 1 and feminin? magnet NS of the afm of *wha camoe G, retaining magnet endeng spew atve the brush which sweeps oval the row e'minals represenng T311@ :si: un'sdgts U- mm@ numbers. The sise@ "ping magnet of the controlla? G1 in :,eplzmiu ing api." impus-s si current from 1th@ battery MQ :the "mk colndnaiw)rsy tia '43'9- mfata the shorsepnagnet of the 6.6210@ advanced into operative relation t9 the EGW 8 of terminals in the, ist bank, pe- Santing ofceNo. Q8, the brush will have advanced to 'the emna goune by the 4G oce key` depressed, und the cubo relay 181 W heme operated, opening the cixqu', of the @pauw/ing mugnes of the coni/WH@ and renmvnfg @umani from the operating; magnet of 151e Selector. lThe stm'ng Why li again operates, this time in conf ,'nclm 'wnh h@ cut-@iff Relay 1%? and appm momrcnizary impulse' xom the baey rulk conuctors to operaie p0 y 148 a?, the ofi/ce selec'of, 'WT

1 circu for the lifting heenf'er zeceives Curren mm1.. Wires Gf 'busy ag'unl; iief coni lpwzu' 'm'ovemen the .1a idle trunk ne is reachac, Wha-m @comes denergze, @planing 1h02 she ing magnet and xpplyr 5 is 0f t."

@.fce adapted to pick out a connecfm capable untn wh the Galed ine. Tha smaning opemfms of seecten may be conm-@Hed by G5 sending apparatus, such as shown in me from 1U Munk:

conductors 'm 270, which Wag exfmgiraed the ogsaf tion of the ofsa ksybfvari, zum Said relay" e'ecfas this -opemtim o the magn of the milio@ my@ resine fepresse,

mfse N Said eay may he of *ibs sending a; L

C Fa the system :mg app@ ma claimed iii @hay desire to r-e @L as 12;@ im zmas .-h Me;-

it @fnac-z, L v

and adapted under control thereof, to cause the sequence of selecting operations by said district selector and otlice selector required to select the trunk line lendingr to the ollice designated bygsuch key.

3. .ln e telephone exchange system, the combination with telephone lines terminating at centraloliices, said central ollices beingr divided into districts, of a talking circuit, district and ollice selecting devices, trunk lines leading from a. district selectingl device to dilferent. oliice selecting devices, said district selecting device being,r adaiited to unite said talking circuit with a trunk line leading to un etlice selectingr device in .a desired district, trunk lines leading fromy the oflice selecting;r devices to the dilferent central offices, said selected office selectingr device being adapted to unite scid trunk line and said talking circuit with :i trunk line leading to a desired ollice, keys representingr the digits of districts and oilices, and means controlled by said keys for selectively operating said selectingdevices.

4. in a telephone exchange system, the combination with telephone lines extending to central olliccs,v said central oiiices being arranged in districts, ot an operators con-- necting circuit et a given central oflice., a connection switch for unitingr said connect ing circuit with e ceiling line, ay district selector forming the terminal of said ccn ecting' circuit, oliice selectors end trunk v.lines leading therefrom to the diil'erent oftices, such district selector being adapted to select nn oflice selector in the particular district, anda keyboard adapted 'to be actin ated by the operator to selectively operate said district selector and tlie'oillce selector selected thereby, to unite sncli connecting circuit with :i trunk line leading to the oi lice in which the called line terminates.

In a telephone exchange system, the combination with telephone lines extending?, to central oliiccs, seid central, ollices being divided into districts, oil'- a talkingr circuit, :i district selecting device, oilice selecting de vices, trunk lines lending' :from seid selecting devices to the different central otlices, said district selecting device being.,v adapted to unite said talking circuit with an oflice selecting device in a particolar district, such oilice selecting device being adapted to unite with a trunk line leading to n desired office, keys representing the digits of the `oflice numbers, ineens controlled by it de pressed oiiieelfey for operating: seid district f selectinLgr device to select an ollice selector in the district wherein s d ollice is located, and means also controlliating the selected ofliceselecting device to, select a trunk line lending to the desired ollice.

6. The combination with telephone lines extending to central ollices, said offices being este lkeys representing the digits i i a i bers, and controlling mer in corriunction with a depri by said key for oper usw/o1 divided into districts, e talking circuit, e district selecting device, otlice selecting de vices, said district selecting device being :adapted to select an. ollice selecting device in lany desired district :ind unite seid talking circuit therewith, trunk lines leading from tbe ollce selecting; devices to the different central offices, the selected ollice selecting de-A `vice being adapted to unite said talking circuit w'itlifi trunk. line lending to the desired o'lice, and a pair of controllers adapted when to successively uctnate said district selecting device and the olice selectin device selected thereby to unite said te king circuit. with a desired milice 7. llie combination with telephone lines extending to cent il ollices, scid oliices being divided into districts.,I :t talking circuit, u district selecti g device, oflice selecting devices, trunlr lines leedin r from the ollice r-=electing devices to the dificrent central offices, and a pair of controllers operating successively in association with the district selectingf device to imite said talking circuit with r esired office selecting device, seid controllers thereupon operating in conjunction with said silice selecting device to connect said talkin(Y ci enit with a trunk l e ing to the desired ollicc.

il. The combination 'with telephone lines ling-to central ollices, said olliccs being divided into districts, a talking circuit, a district selecting device, oliice selecting dericesf` trunk lines leading from tlic ollice selecting devices to the diterent central i oflices, and selecting ineclninisn'i adapten. when set to operate seid dis riot selecting device to unite iid tellring 'cuit with an oi'iice ,selecting deviceina particular district, and thereupon, nctnete said selected ollice eef lecting device to unite said talking ci.' nit with e trunk line lending to the desireiil ollice in seid district.

3, Tlie con'iliinatiori with telephone extending to central oilic, 'fl` lY "u di idcd into distrie di trict selecting de vices, trunk lines lending; lror lecting devices to tbe ilitl'erci:

ne et o "il illic e,

Y e num miniem operating d key to actu ate said district sxalccting device and unite seid talking circuit with an office selecting device in the district where-in the oflice rcpresented by seid depressed key lies, saidcom trolling; nieclmnisni thereupon operating said office selecting devic to unit-e said teile ing circuit with a trunk line lending to the silice represented by seid key.

l0. The combination wit-li telephone lines extending; to centralv oliices, seid offices being divided. into districts, s. talking ci ruit, e district selec,` ice, office er: ,g de" vices, triinlr lines ieinling from the silice eelee-ting devices to the different `central offices, keys representing digits of the office numbers, a: pair of controllers selectively operated by-a' given oflicekey for actuating said district selecting device to unite said talking circuit with an office selecting device in the district to which the office represented by said key belongs, and means for causing said controllers to again operate units of a district in which said office lies,`

means controlled by said key and the altered terminals for operating said district selecting device to unite said talking circuit with an office selecting device in said district, rows of terminals representing digits of office numbers, means controlled by an office key for altering the electrical condition of the terminals in said rows corresponding to .the digits of the office represented by said key, andrmeans controlled by the depressed ofiice key and the altered terminals in said rows for operating said selected office switching device to unite said talking circuit With a trunk line leading to the office represented by said key.

l2. Tile combination -with telephone lines extending to central offices, said offices being' divided into districts, of a talking circuit,

` a' district selecting device, office selecting devices. trunk lines leading from the office selecting devices to the different central offices, a pair of controllers G G1, a roW (,l of terminals in controller G representing tens digits of the districts, a row clA of terminals in cont-roller G1 representing the units digits of the districts, office and district keys as;`

sociatcd with the controllers' (i and G1, means controlled b y a given office key when operated for altering the electrical condition .of terminals in said rows representing -the Idistrict in which'the said office lies, means controlled by said altered terminals and said key for operating Asaid district' selecting device to unite the 'talking lcircuit with an office selecting device in the-district in which the office represented by said key lies, a row l of terminals in controller G representing the tens digits of the office numbers,a row Z1 of terminals in 'controller G1 representing the units digits ofthe offices, means controlled by a given office key for altering the electrical eonitionef the terminals in seid rows representing the digits of the office represented by said-key, and means actuated, when-V the office selecting device has been selected, under the control of said-key and said altered terminals, for operating said office selecting device to unite said talkin circuit with a trunk line leading to the office corresponding to said key.

13. The combination with telephone lines extending to a number of central offices, of line switching mechanism at each of said central offices, a talking circuit, office selecting mechanism, one of said sending apparetuses adapted toA operate selected line switching mechanism, one of said sending apparatuses being adapted normally to serve said talking circuit, an office keyboard normally associated with said sending apparatus adapted to operate said office selecting mechanism to unite said talking circuit with line switching mechanism at a desired office, and means, automatically operated when said office keyboard has completed its work, for transferring the same into association with the other sending apparatus.

14. T he :combinationwith telephone lines extending to a -number of central offices, of line switching mechanismat each of said central offices, a-talking circuit` office selecting mechanism, a pair of sending apparatuses adapted to operate the selected line switching mechanisms, oneof said sending apparatuses being adapted normally to serve said talking circuit, an office keyboard normally associated with said sending apparatus adapted to operate said office selecting 'mechanism to unite said talking circuit with line switching mechanism at e desired officef: a relay adapted to transfer said. office keyi board to the other'sending apparatus, and 'a circuit for said relay completed when said selecting mechanism has united said talking circuit with the line switching mechanism of a desired offi'c'e.

l5. The combination with telephone lines extending to a number of central offices, of

lineswitching mechanism ateach of said.

central ofices,a talking circuit, office selcff' ing mechanism, a pair of sendiing apparatuses adapted. to operate the "slected line switching mechanisms,.one of said sending apparatuses beingadapted normally to serve said talking circuit, an officekeyboard normally associated Withsaid sendingA apparatus adapted to operate saidofce selecting mechanism to unite said talking circuit with 4 line switching mechanism at a desired office,-

means automatically 'operatedwhen said- 'keyboard has completed its work for transf` ferring the same to the other sending apparatus, and means automatically operatedwhen said first mentioned sending apparatus has operated the selected line switching mechanism tourer-associating said office-key; 

